[osg-users] osgText precision issue

sherman wilcox wilcox.sherman at gmail.com
Sat Sep 8 13:11:17 PDT 2007


Yeah, that sounds like it will do the trick. I'll have to re-work some
code, but that should address the issue.

On 9/8/07, Jason Beverage <jasonbeverage at gmail.com> wrote:
> Hi Sherman,
>
> The issue you're seeing is probably a precision issue since OpenGL works in
> floats.  I've seen a similar effect with Text objects in my applications.
> One way to reduce this precision problem is to to not position your text
> using the setPosition function but to position it by using a MatrixTransform
> as the parent of the geode containing your text.  This will allow OSG to
> accumulate the transformation and camera matrices in doubles and only
> convert to float the very last moment to increase precision.  It is the same
> technique that osgdem uses when managing its tiles.
>
> Hope this help!
>
> Jason
>
>
> On 9/8/07, sherman wilcox <wilcox.sherman at gmail.com> wrote:
> >
> > I'm having a bit of trouble with mangled text if I zoom in to close.
> > This text is on an osgDem generated ellispoid. In the attached
> > screenshots, the text appears correctly in text2.jpg. However, in
> > text3.jpg you'll see the problem. This only occurs if I zoom in really
> > close to the text. If I back off the camera a bit, the text reverts
> > back to the correct state.
> >
> > My questions are:
> >
> > 1) What's causing this?
> > 2) How best to address the issue?
> >
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> >
> >
>
>
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